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Diffstat (limited to 'src/util/dict_surrogate.c')
| -rw-r--r-- | src/util/dict_surrogate.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/src/util/dict_surrogate.c b/src/util/dict_surrogate.c new file mode 100644 index 0000000..a23cba3 --- /dev/null +++ b/src/util/dict_surrogate.c @@ -0,0 +1,180 @@ +/*++ +/* NAME +/* dict_surrogate 3 +/* SUMMARY +/* surrogate table for graceful "open" failure +/* SYNOPSIS +/* #include <dict_surrogate.h> +/* +/* DICT *dict_surrogate(dict_type, dict_name, +/* open_flags, dict_flags, +/* format, ...) +/* const char *dict_type; +/* const char *dict_name; +/* int open_flags; +/* int dict_flags; +/* const char *format; +/* +/* int dict_allow_surrogate; +/* DESCRIPTION +/* dict_surrogate() either terminates the program with a fatal +/* error, or provides a dummy dictionary that fails all +/* operations with an error message, allowing the program to +/* continue with reduced functionality. +/* +/* The global dict_allow_surrogate variable controls the choice +/* between fatal error or reduced functionality. The default +/* value is zero (fatal error). This is appropriate for user +/* commands; the non-default is more appropriate for daemons. +/* +/* Arguments: +/* .IP dict_type +/* .IP dict_name +/* .IP open_flags +/* .IP dict_flags +/* The parameters to the failed dictionary open() request. +/* .IP format, ... +/* The reason why the table could not be opened. This text is +/* logged immediately as an "error" class message, and is logged +/* as a "warning" class message upon every attempt to access the +/* surrogate dictionary, before returning a "failed" completion +/* status. +/* SEE ALSO +/* dict(3) generic dictionary manager +/* LICENSE +/* .ad +/* .fi +/* The Secure Mailer license must be distributed with this software. +/* AUTHOR(S) +/* Wietse Venema +/* IBM T.J. Watson Research +/* P.O. Box 704 +/* Yorktown Heights, NY 10598, USA +/*--*/ + +/* System library. */ + +#include <sys_defs.h> +#include <errno.h> + +/* Utility library. */ + +#include <mymalloc.h> +#include <msg.h> +#include <compat_va_copy.h> +#include <dict.h> + +/* Application-specific. */ + +typedef struct { + DICT dict; /* generic members */ + char *reason; /* open failure reason */ +} DICT_SURROGATE; + +/* dict_surrogate_sequence - fail lookup */ + +static int dict_surrogate_sequence(DICT *dict, int unused_func, + const char **key, const char **value) +{ + DICT_SURROGATE *dp = (DICT_SURROGATE *) dict; + + msg_warn("%s:%s is unavailable. %s", + dict->type, dict->name, dp->reason); + DICT_ERR_VAL_RETURN(dict, DICT_ERR_RETRY, DICT_STAT_ERROR); +} + +/* dict_surrogate_update - fail lookup */ + +static int dict_surrogate_update(DICT *dict, const char *unused_name, + const char *unused_value) +{ + DICT_SURROGATE *dp = (DICT_SURROGATE *) dict; + + msg_warn("%s:%s is unavailable. %s", + dict->type, dict->name, dp->reason); + DICT_ERR_VAL_RETURN(dict, DICT_ERR_RETRY, DICT_STAT_ERROR); +} + +/* dict_surrogate_lookup - fail lookup */ + +static const char *dict_surrogate_lookup(DICT *dict, const char *unused_name) +{ + DICT_SURROGATE *dp = (DICT_SURROGATE *) dict; + + msg_warn("%s:%s is unavailable. %s", + dict->type, dict->name, dp->reason); + DICT_ERR_VAL_RETURN(dict, DICT_ERR_RETRY, (char *) 0); +} + +/* dict_surrogate_delete - fail delete */ + +static int dict_surrogate_delete(DICT *dict, const char *unused_name) +{ + DICT_SURROGATE *dp = (DICT_SURROGATE *) dict; + + msg_warn("%s:%s is unavailable. %s", + dict->type, dict->name, dp->reason); + DICT_ERR_VAL_RETURN(dict, DICT_ERR_RETRY, DICT_STAT_ERROR); +} + +/* dict_surrogate_close - close fail dictionary */ + +static void dict_surrogate_close(DICT *dict) +{ + DICT_SURROGATE *dp = (DICT_SURROGATE *) dict; + + myfree((void *) dp->reason); + dict_free(dict); +} + +int dict_allow_surrogate = 0; + +/* dict_surrogate - terminate or provide surrogate dictionary */ + +DICT *dict_surrogate(const char *dict_type, const char *dict_name, + int open_flags, int dict_flags, + const char *fmt,...) +{ + va_list ap; + va_list ap2; + DICT_SURROGATE *dp; + VSTRING *buf; + void (*log_fn) (const char *, va_list); + int saved_errno = errno; + + /* + * Initialize argument lists. + */ + va_start(ap, fmt); + VA_COPY(ap2, ap); + + /* + * Log the problem immediately when it is detected. The table may not be + * accessed in every program execution (that is the whole point of + * continuing with reduced functionality) but we don't want the problem + * to remain unnoticed until long after a configuration mistake is made. + */ + log_fn = dict_allow_surrogate ? vmsg_error : vmsg_fatal; + log_fn(fmt, ap); + va_end(ap); + + /* + * Log the problem upon each access. + */ + dp = (DICT_SURROGATE *) dict_alloc(dict_type, dict_name, sizeof(*dp)); + dp->dict.lookup = dict_surrogate_lookup; + if (open_flags & O_RDWR) { + dp->dict.update = dict_surrogate_update; + dp->dict.delete = dict_surrogate_delete; + } + dp->dict.sequence = dict_surrogate_sequence; + dp->dict.close = dict_surrogate_close; + dp->dict.flags = dict_flags | DICT_FLAG_PATTERN; + dp->dict.owner.status = DICT_OWNER_TRUSTED; + buf = vstring_alloc(10); + errno = saved_errno; + vstring_vsprintf(buf, fmt, ap2); + va_end(ap2); + dp->reason = vstring_export(buf); + return (DICT_DEBUG (&dp->dict)); +} |